Wood defibering apparatus



Oct. 29, 1957 A. l.. MoTTET woon DEFIBERING APPARATUS 5 Sheets-Sheet 1 Filed June 15. 1953 f .e T mo. MM; zL P f s gw A QN l ww I n 12 Q n 7.19 1 vw. U ull Q m u D A M -u a Ilm" w w il. .J Qi v Gm. .Qm.\ |m Q n Q ml. M r e M 1; D mi Q n Q i FT F. uw

Oct. 29, 1957 A. L. MoTTl-:T

WOOD DEFIBERING APPARATUS Filed June 15, 1953 I5 Sheets-Sheet 2 Oct. 29, 1957 A. L. MoTTl-:T

WOOD DEFIBERING APPARATUS 3 Sheets-Sheet 5 Filed June 15, 195,3

INVENTOR. mh url. .Mozl e BY 2,811,183 woon Dnrrnnnnso APPARATUS Arthur L. Mottet, Longview, Wash., assignor, by mesne assignments, to International Paper Company, New York, N. Y., a corporation of New York Application June 15, 1953, Serial No. 351,480

Claims. (Cl. 144-162) This invention relates to apparatus for detibering wood, i. e. for reducing it to fibrous form, useful lin bulk or in the manufacture of pressed fiberboard, such as insulation board or hardboard.Y Y

In one important method of .making hardboard, wood is reduced to the form of crosscut fibrous elements orpiiakes by cutting it, with the cut being parallel to the grain direction and the direction of the cutting traverse being across the grain direction, preferably at about right angles thereto. The resulting crosscut flakes have lengths determined by the'lengths ofthe knives employed or-the spacing of scoringelements whichvmay be employed in conjunction with the knives. Their thickness is determined by such factors as the setting'of the knives, the feed rate, the number of knife strokes per unit time, etc.

The width of the liakes is random, depending upon the thickness of the pieces of wood from which they are cut, and theV severity of` subsequent handling operationswhich may break the akes along the grain. To-formtheminto berboard, the flakes are classified as to size, coatedwith a suitable binder, formed into a mat, and hot pressed to the desired density. Y

.l To obtain a hardboard product of maximum properties, it is'essential that the defbering operation be controlled carefully to produce flakes'of uniform dimensions. This is diiicult to do in commercial defibrators because of the high degree of vibration necessarily present; because of the diiculty of feeding the Wood pieces at a uniform rate; and because of the tendency of the wood to splinter, particularly during the reduction of the last portion of each wood piece.

As a result, there is formed a conglomerate product of flakes having non-uniform dimensions together with slivers, splinters, and wood in granular and powdered form. When this is felted andpressed into hardboard, the resulting pressed product is correspondingly non-uniform in strength and density and is characterized by the presence of surface defects caused by the inclusion of sticks and slivers. Y

-It therefore is a primary object of the present invention to provide apparatus which will produce fibrous elements from wood, particularly crosscut flakes, which are of predetermined dimensions and are relatively free from sticks and slivers. l

It is another object of the present invention to provide apparatus for defibering wood which is adjustable easily and accurately to produce fibrous elements of the prede"- termined dimensions at the desired production rate.

Still another object of the present invention is the provision of wood defibering apparatus which is adaptable for use in the reduction to fibrous form of the woods of various species of trees and of various moisture content ranging from green wood to dry wood. w 1f Still another object of this invention is the provision of wood defibering apparatus which has a high production rate although the apparatus itself is relatively small in size and inexpensive reconstruct. j -j rates Y Patent i ri ice Y It is another object of thel present invention to provide wood delibering apparatus adaptable for use 1n maklng crosscut, fibrous elementsV or flakes from kiln dry'wood.

scraps, such as planer ends. j

Another object of the present invention is the provision of wood defibering apparatus which holds the wood securely during the cutting operation making the same relatively safe while contemporaneously producing a fibrous product of high quality.

The manner irl-which the foregoing and other objects of this invention are accomplished will be apparent from the accompanying specification and claims, considered together with the drawings, wherein: l

Figure l is a plan view of the presently described wood defibering apparatus;

Figure 2 is a view in side elevation of the apparatus illustrated in Figure l, the planes of rotation of the cutter head surface and the cutting knives being shown by dotand-dash lines;

Figure 3`is a plan view of alternate wood hold-down means for use in the apparatus of Figures l and 2;

Figure 4-is a side elevational view, partly in section, taken along the line 4 4 of Figure 3; and

Figure 5 is an enlarged fragmentary view in sideelevation of the cutting area of the apparatus, showing the relationship between the cutter head, cutting knife and wood block, the positions of the cutting knife and block just Vpreceding the cutting operation being shownby dotted lines.

V'As is illustrated inthe drawings the presently described wood deiibering vapparatus is provided with cutting meansl mounted on the frame 10 of the apparatus. V.Although the.V

cuttingmeans may comprise'anyv suitable type of recipro eating orV rotary cutter, it .preferably .comprises Vaf rotary cutter head ofthe type indicated genertilly'-atl2.n Inthe body of the cutter head there` are setat .spacedlintervalsl` a plurality of knives 14;V `Alternating'with;the knives at.

spaced-intervals about the periphery of` thecut't'eiliead are the scoring points 16. These'may berspacedapartV as desired to determine the length ofthe fibrous,elements` cut from the wood by tthe` cutter head. A hopper `17-or other receiving means is placed below the cutterhead;

The blocks of wood 24 which are fed to the cutter.

head may be of any species and have any moisture content ranging from green wood to kiln dry wood. As hasl been indicated above, however, the apparatus is designed particularly for use with kiln dried ywood scraps, such as planer ends, which are cut to pieces of substantially uniform length. These pieces are fed into a bed, vthe width of which is determined by a pair of elongatedguide strips 26, directed toward the cutter head and provided with outwardly flared sections at their outer ends.

Onthe bottom ofrthefeeding bed are a pair of spacedk apart tracks 30, which are located within the guideplates 26, and are substantially parallel thereto. At the outfeed end of the feeding bed and adjacent the cutter head 12 is a bed plate 34 over which the wood pieces pass as they are reduced to fibrous form.

the hold down` means comprises a tloating'hold down 'plate 36 Vdimensioned to overlie the Wood blocks containedir'ini the apparatus. lt preferably ismadeof a` heavy material,

although if its yweight isnot sutiicient to hold"dol\vn'thelv pieces; effectively, it maybe in reasedbytplacing.ioniits been substantially entirely reducedfto Vfibrousfelements.V

In Ithe form illustrated .infFigur'es l and 2, the resilient hold down means may comprise a pluralityof leaf springs 40 attachedt'o the end of hold down plate 36 and directed downwardly into engagement with the wood blocks. The springs are spaced apart longitudinally of the apparatus so Vthat they contact each block in several places, assuring that it will be held securely. Y

' In the form illustrated in Figures 3 ,and 4, the resilient means for holding down the wood blocks as they are reduced by the cutting means comprise a pluralityof dogs 42 of varying lengths and having pointed ends which engage the upper surfaces of the wood blocks. The dogs are pivotally attached to a common shaft 44 mounted on arms 46, which in turn are attached to the frame member 50.

i The dogs are arranged in groups as indicated in the drawing to engage each block of wood at a number of spaced apart points. Each dog within a given group is separated from the other members of the group by means of a spacer S2, and the groups are maintained separate from each other by means of collars 54.

Resilient means are provided for maintaining the dogs resiliently in contact with the wood blocks. These may comprise comb-shaped leaf spring assemblies 56, each of which is bolted to the frame member 50, and provided with a plurality of unit leaf springs 58, which are spaced apart from each other and which resiliently engage the dogs 42 in the manner illustrated in Figure 4.

Drive means are provided for driving the blocks, at a predetermined and uniform speed in the direction of the cutter head. The drive means illustrated comprises lower and upper assemblies engaging respectively the lower and upper surfaces of the blocks.

The lower assembly comprises a pair of spaced apart endless chains 60 provided with spaced apart spurs 62 and stationed within and parallel to guideA members 26. The chains engage forward sprockets 64 and rearward sprockets 66 rotatably mounted, respectively, on shafts 68, 70. The upper or working stretches of the chains ride on and are supported by tracks 30, and accordingly are reinforced for supporting blocks 24 resting thereon.

The upper drive assembly comprises a pair of spaced apart, endless drive chains 72 placed above and parallel to the lower drive chains 60. Like the lower chains, the upper chains are provided with outwardly extending spurs 74 adapted to engage the surfaces of the blocks, Chains 72 are mounted on forward sprockets 76 and rearward sprockets 78 rotatably mounted respectively on the rotatable shafts 80, 82. These shafts are journalled, respectively, within bearings fixed to the forward and rearward portions, respectively, of hold down plate 36.

The upper drive chains 72, mounted on the floating hold down plate, which moves vertically depending upon the thickness of the blocks passing beneath it, are driven through a pair of spur gears 84 fixed to the ends of shaft 80. Gears 84 mesh with and are driven by spur gears 86 keyed to a shaft 88 which is journalled in bearings attached to the frame of the apparatus. Shaft 80 is maintained a working distance away from shaft 8S with the teeth of gears 84 and 86 in proper meshing relationship with each other by means of the link members 90.

The upper and lower drive chains are driven synchronously with each other at the proper speed through a drive consisting of chain 92 interconnecting a sprocket 94,V keyed to shaft 68 and a sprocket 96 keyed to shaft 88. Shaft 6.8 in turn is driven through a chain 98 connected to the Y are supported by tracks 30.

shaft of a variable speed drive 100 operated by a motor 102.

As stated hereinbefore, the blocks 24 are moved toward the cutter knives 14 positively and at a uniform but adjustable rate of speed which is determined by selective adjustment of the variable speed drive 160 of motor 102. As indicated in Figure 2 of the drawings, and best illustrated in Figure 5, the speed of forward movement of the block toward the cutter head 12 is such, with respect to the rotational speed of the cutter head, that each successive scoring and cut is made before'the block has moved into abutment with the surface of the cutter head, This is indicated in Figure 5 by the dotted line positions of the block 24 and knife 14. Thus, the depth of the scoring and cut is determined by the relative speed of the cutter head motor 22 and the motor drive 100 of the drive chain motor 162, it being necessary only to adjust the projection of the cutter knives 14 and scoring points 16 from the surface of the cutter head 12 a distance greater than the desired thickness of cut. In this manner a space is maintained between the forward surface of the block being out and the surface of the cutter head. This manner of operation achieves the objectives mentioned hereinbefore, namely it provides maximum precision of control for the production of high quality flakes of predetermined but variable thickness; it reduces to a minimum the production of sticks and slivers by eliminating frictional contact between the block and cutter head; and it provides such production with a minimum of power by eliminating power Waste which otherwise results from the friction of the block against the surface of the cutter head.

Operation The operation of the presently described apparatus is as follows:

First the knives 14 of cutter head 12 are adjusted to the desired depth. y Then the scoring points 16 are spaced apart to the desired degree and the cutter head rotated at the selected speed by motor 22. Wooden blocks, Yfor example planer ends cut to size to iit between the guide members 26, then are stacked in as many tiers as is expedienton the upper stretches of drive chains 60 which The variable speed drive 100 then is set at the desired operating rate. It drives chain 98, which in turn rotates shaft 68 carrying sprockets '64, which drive the lower feed chains 60. Sprocket 94 on shaft 68 drives sprocket 96 on shaft 88. Shaft 88 mounted on the frame of the apparatus carries spur gears 86 which engage spur gears 84 keyed to shaft 80. Shaft 88 mounted on the frame of the apparatus and shaft 80 mounted on the oating hold down plate 36 are maintained in proper working relationship to each other by means of the link members 90.` Sprockets 76 keyed to `shaft 80 engage and drive the upper feed chain 72. Accordingly, chains 69 and 72 are driven syn-` chronously with their working stretches in contact respectively with the lower and upper surfaces of blocks 24 urging them in the direction of the cutter head. The particular block being reduced to fibrous form by the cutter head is maintained securely against bed plate 34 by means of the hold down springs 40.

As a result the block is held securely and the knives of l the cutter head shave from it crosscut akes uniformly of the desired dimensions with a minimum formation of sticks and slivers. Furthermore the grain and the dimensions of the cut iiakes are widely variable to suit a particular apferred example of the same, and that various rchanges in the shape, size and arrangement of parts may be resorted to, without departing fromthe spirit of my invention, or the scope of the subjoined claims.

Having thus described my invention, I claim:

l. Wood defibering apparatus comprising a main frame, power driven cutting means mounted on the main frame for reducing wood pieces to fibrous form, a bed plate on the main frame stationed adjacent the cutting means for supporting the wood pieces as they are cut, lower drive chain means mountedjon the main frame and having its upper stretch arrangedY firmly to support and deliver the Wod pieces to the bed plate, a floating hold down assembly including' a freely fioating hold down frame, upper drive chain means mounted on the hold down frame parallel to the ,lower drive chain means and having its lower stretch arranged firmly to engage the upper surfaces of the wood pieces, resilient finger means mounted on the hold down frame and projecting therefrom above the bed plate for substantial pressure contact with the upper surfaces of the Wood pieces supported on the bed plate adjacent the cutting means, first drive means mounted. on the main frame and connected to the lower drive chain means, second drive means mounted on the hold'down frame and connected to the upper drive chain means, radius link means pivotally interconnecting the first and second drive means for maintaining them a fixedpdistance apart while permitting the second drive means to rotate about the axis of the first drive means, thereby permitting the floating hold down assembly freely to move vertically to accommodate wood pieces of diverse thicknesses between the working stretches of the upper and lower drive chain means, means interconnecting the first and second drive means for simultaneous rotation, and motor means connected to one of the drive means for driving synchro-nously the upper and lower drive chain means.'

2. The apparatus of claim l including means for controlling the relative driving speed of the cutting means and the drive chain means for regulating the thickness of cut.

3. Wood defibering apparatus comprising a main frame, power driven cutting means mounted on the main frame for reducing wood pieces to fibrous form, a bed plate on the main frame stationed adjacent the cutting means for supporting the wood pieces as they are cut, lower drive chain means mounted on the main frame and having its upper stretch arranged firmly to support and deliver the wood pieces to the bed plate, a floating hold down assembly including a freely floating hold down frame, upper drive means mounted on the hold down frame parallel to the lower drive chain means and having its lower stretch arranged firmly to engage the upper surfaces of the wood pieces, resilient finger means mounted on the hold down frame and projecting therefrom above the bed plate for substantial pressure contact with the upper surfaces of the wood pieces supported on the bed plate adjacent the cutting means, first gear means mounted on the main frame and connected to the lower drive chain means, second gear means mounted on the hold down frame and connected to the upper drive chain means, radius link means pivotally interconnecting the first and second gear means for maintaining them intermeshed while permitting the second gear means to rotate about the axis of the first gear means, thereby permitting the oating hold down assembly freely to move vertically to accommodate wood pieces of diverse thicknesses between the working stretches of the upper and lower drive chain means, and motor means connected to one of the gear means for driving synchronously the upper and lower drive chain means.

4. Wood defibering apparatus comprising a main frame, power driven cutting means mounted on the main frame for reducing wood pieces to fibrous form, a bed plate on the main frame stationed adjacent the cutting means for supporting the wood pieces as they are cut,

lower drive chain means mounted onv the main frame and 'having its upper stretch arranged firmly to support and ldeliverthe wood pieces to the bed plate, chain'way means on the main frame supporting a substantial portion of the upper stretch of the lower drive chain means against sagging, a floating hold down assembly including a freely floating hold down frame, upper drive chain means mounted on the hold down frame parallel to the lower drive chain means and having its lower stretch arranged firmly to engage the upper surfaces of the wood pieces, chain way means on the hold down frame supporting a substantial portion of the lower stretch of the upper drive chain means against upward buckling, pressure exerting means on the hold down assembly for preventing upward buckling of the wood pieces, wood gripping means on at least one of the upper and lower drive chain means for securing the wood pieces firmly thereto whereby to inhibit rearward movement of the wood pieces due to rearward thrust exerted by the cutting means, resilient finger means mounted on'the hold down frame and projecting therefrom above the bed plate for substantial pressure contact with'the upper surfaces of the wod pieces supported on the bed plate adjacent the cutitng means, the linger means functioning to hold the wood pieces firmly on the bed plate during cutting and to resist forward movement of the wood pieces toward the cutting means, whereby the wood pieces carried between the upper and lower drive chain means are held in firm abutment with each other and are moved toward the cutting means at a predetermined rate of speed, first drive means mounted on the main frame and connected to the lower drive chain means, second drive means mounted on the hold down frame and connected to the upper drive chain means, radius link means pivotally interconnecting the first and second drive means for maintaining them a fixed distance apart while permitting the second drive means to rotate about the axis of the first drive means, thereby permitting the oating hold down assembly freely to move vertically to accommodate wood pieces of diverse thicknesses ,between the working stretches of the upper and lower drive chain means, means interconnecting the first and second drive means for simultaneous rotation, motor means connected to one of the drive means for driving synchronously the upper and lowerdrive chain means, and means for controlling the relative driving speed of the cutting means and the drive chain means for regulating the thickness of cut.

5. Wood defibering apparatus comprising a main frame, power driven cutting means mounted on the main frame for reducing wood pieces to fibrous form, a bed plate on the main frame stationed adjacent the cutting means for supporting the Wood pieces as they are cut, lower drive chain means mounted on the main frame and having its upper stretch arranged firmly to support and deliver the wood pieces to the bed plate, chain way means on the main frame supporting a substantial por-Y tion of the upper stretch of the lower drive chain means against sagging, a fioating hold down assembly including a freely fioating hold down frame, upper drive chain means mounted on the hold down frame parallel to the lower drive chain means and having its lower stretch arranged firmly to engage the upper surfaces of the Wood pieces, chain way means on the hold down frame supporting a substantial portion of the lower stretch of the upper drive means against upward buckling, pressure exerting means on the hold down assembly for preventing upward buckling of the wood pieces, wood gripping means on at least one of the upper and lower drive chain means for securing the wood pieces firmly thereto whereby to inhibit rearward movement of the wood pieces due to rearward thrust exerted by the cutting means, resilient finger means mounted on the hold down frame and projecting therefrom above the bed plate for substantial pressure contact with the upper surfaces of the wood pieces supported on the bed plate adjacent the cutting means, the finger means functioning to hold the wood pieces firmly on the bed plate during cutting and to resist forward movement of the wood pieces toward the cutting means, wherebyl the wood pieces carried between the upper and lower drive chain means are held in rm abutment with each other and are moved toward the cutting means at a predetermined rate of speed, first gear means mounted on the main frame and connected to the lower drive chain means, second gear means mounted on the hold down frame and connected to the upper drive chain means, radius link means pivotally interconnecting the rst and second gear means for maintaining them intermeshed while permitting the second gear means to rotate about the axis of the tirst gear means, thereby permitting the floating hold down assembly freely to move vertically to accommodate wood pieces of diverse thicknesses between the working stretches of the upper and lower drive chain means, motor means connected to one of the gear means for driving synchronously the upper and lower drive chain means, and means for controlling the relative driving speed of the cutting means and the drive chain means for regulating the thickness of cut.

References Cited in the tile of this patent UNITED STATES PATENTS Andrews Nov. 2l, Mayberry Oct. 19, 'Harris Ian. 3,v Linderman Oct. 1, Baker Nov. 19, Merrill May 31, Peterson Apr. 4, 'ThomasY Apr. 15, Garner Nov. 28, Merrill Apr. 10, Shellenberger Mar. 6, Rawson Aug. 14, Street May 19, Neal Oct. 5, Mitchell Feb. 20, Gustin May 13, Bacon Ian. 6, Joa Apr. 4, Elmendorf Oct. 9, Pasquier May 6, Smith Nov. 4, Alexander Sept. 15,

FOREIGN PATENTS Germany May 12, Sweden May 20, 

